For good endurance and maximum distance, a pedaller of a bicycle, for example, must strike an appropriate balance between pedal force, i.e. the force applied by the foot to the pedal, and cadence, i.e. the number of pedal strokes per unit time. Ideally, this balance should be maintained constant throughout the ride. That is, the pedal force and cadence should both remain constant. This is usually accomplished in outdoor conditions of varying slope and wind by appropriately changing gear ratios in a multi-speed bicycle.
It is difficult for a bicyclist to accurately estimate cadence. The difference between cadences of 80 and 140 strokes per minute (40 to 70 revolutions per minute of the pedal crank) is difficult to detect without instrumentation, but such differences may have a serious impact on the energy output of a cross-country bicyclist.
Since bicycles are frequently left unattended, bicycle accessories are frequently subject to theft.
In addition, any solution should be simple and quick to install without requiring mounting and interconnection of a large number of parts.